1. Field of the Invention
The present invention concerns the provision of bulged structures constituted by a casing with in particular a hemispherical shape and externally covered with resistant fibers possibly bound together by a settable binder.
The invention applies more specifically, but not exclusively, to the provision of storage vessels for fluids under pressure and in particular vessels known as gas storage "bottles", these gases being air, oxygen, nitrogen, carbonic acid used in various industrial sectors.
2. Discussion of Background Information
This type of vessel comprises a central cylindrical hoop provided with bulged end portions, generally hemispheric, the entire structure being reinforced by means of resistant fibers bound together by a settable binder.
One of the end portions comprises at its central portion a passage hole so that the reinforcement of the bottle end portions is embodied by making a reserve on the top portion of the two hemispheres of the end portions.
The current technique for filament laying used for embodying such a structure consists of a simple winding with an elementary pattern during which the filament to be laid passes only once on the hemispherical cap, the passage being uninterruptedly repeated with a slight angular shift as many times as there are filaments on the layer.
The drawback of this technique resides in the filament accumulating at the periphery of the hole of one of the end portions and the dead zone corresponding to the other end portion, the filament thus forming a "bulb", which does not provide a constant thickness when reinforcing these end portions of the bottles.